Centrifugal type pumps



Dec. 22, 1964 H. E. CLARY ETAL CENTRIFUGAL TYPE PUMPS 3 Sheets-Sheet 1 Filed NOV. 17, 1959 fZ'YI EZ'Y/UFE Harry E. Clary Jaseph A, C A/Gill 1964 H. E. CLARY ETAL 3,

CENTRIFUGAL TYPE PUMPS Filed Nov. 17, 1959 3 Sheets-Sheet 2 United States Patent 3,162,136 CENTREUGAL TYPE PUMPS Harry E. Clary, Chester-land, and Joseph A. ONeill, Parma, Ohio, assignors to Thompson Ramp Wooldridge Inc., Cleveland, Ohio, a corporation of Ohio Filed Nov. 17, 1959, Ser. No. 853,649 6 Claims. (Cl. 103-111) This invention relates broadly to pumps of the generally centrifugal type (i.e., radial or mixed) and the method of manufacturing them by die casting and more particularly to the intake portion of the housing therefor and its intake passageways to supply fluid (or preferably liquid) to at least one face or end of the impeller and its generally radially extending blades.

Such a pump may be used to circulate the cooling water for an internal combustion engine of the conventional automotive type, and is usually driven by a pulley on its externally projecting shaft which extends out through the outer or removable housing portion.

This housing portion is usually of conventional cast iron. This removable housing portion encloses at least an end of the pump impeller and its supply or intake chamber (which is usually annular around the shaft) and also includes a transverse passageway extending radially into said liquid entry chamber. This removable housing has generally been secured on a transaxial or transverse parting line to the engine block itself wherein a cavity forms the other or mating portion of the pump housing to enclose the discharge end of the impeller and to include the outlet passageways or volute.

Heretofore, such pumps of the above described conventional automotive types (and of other types and for other applications) have had unduly high manufacturing costs and have had a poor efiiciency, particularly as to the flow conditions for the fluid or the liquid entering the impeller. Such pump housing portions have usually been made of conventionally cast iron requiring substantial subsequent finish machining or interior surfaces (with related handling and labor) and hence have been of higher cost than die castings (preferably but not necessarily of aluminum alloy or other light metals) wherein the substantially automated operation has very low labor costs and produces an accurately cast product substantially in its finished form.

Before the present invention it has not been deemed feasible or economically practicable to manufacture such pumps and particularly their intake housing portions by die casting despite the known desirability and inherent savings of this process. This has been true primarily because of the reentrant surfaces (which have been believed by those skilled in this art to be essential) both in the cavity to receive the pump shaft and its impeller and also in the cavity or recess forming the transverse and intersecting intake passageway.

Previously the liquid entering the impeller has entered from an enlarged or reentrant and annular chamber portion extending all the way around the pump shaft to thus preclude withdrawal of a one-piece rigid die pin from either the intake passageway or from the shaft and impeller recess.

According to the teachings of this invention, the two main and intersecting cavities or recesses (and hence all of the cavities or recesses in such casing or housing portion) may be formed without any reentrant surfaces to impede the removal of one-piece or rigid die pins used in die casting. This removal of the die pins is, in one of the preferred embodiments, accomplished by the proper or sequential removal of the die pins for these two cavi ties. Since the inlet passageway is wrapped, or extends around behind, the cylindrical recess or its impeller entry portion, the die pin for the impeller and its shaft is re moved first before the engaging or wrap-around die pin for the intake passageway is pulled out. Both of these main recesses or cavities have either uniform or progressively decreasing cross-sectional areas in the direction moving inwardly from their outer or insertion ends to further cooperate with the removal of the die pin used in die casting. It will be understood that instead of being of a wrap-around type, the die pin for the inlet cavity can define about half of the inlet chamber and enter a corresponding slot cut into the axial die pin at this region. Further, as illustrated herein, various die casting methods or diflerent total numbers of die pins may be used herein.

In addition to the advantages of die casting, the pump efficiency itself is increased, particularly in the bettering of the flow conditions of the liquid entering the impeller. These better intake conditions are due to the rotational energy gain in the liquid about to enter the impeller while it is in the impeller entry chamber, which in the preferred embodiment as illustrated herein, is of an annular form around the shaft which pre-rotates the fluid.

The partial wrapping of the tangential inlet passage around the entry chamber also pre-rotates the entering liquid, by the directional characteristics of this volute or scroll-like passageway which is of decreasing cross-sectional areas in its direction of flow to give a progressively increasing velocity and energy gain. This entry form also reduces cavitation and turbulence in the entering fluid or liquid.

It will be apparent that the general principles of this arrangement and the increased efiiciency achieved thereby may be useful in other or non-cast types of pumps of this general type and in pumps wherein the flow is no around the impeller shaft.

It will thus be apparent that pumps of this improved type can be economically die cast and have improved eificiencies particularly in their propeller entry passages. They also have smaller impeller entry chambers with a correspondingly smaller diameter in this portion and thus require less material and yet have an equal or better capacity and efficiency.

It is a general object of the present invention therefore to provide an improved pump of this general type whose inlet casing portion can be die cast, preferably of aluminum alloy or other light metals.

Another general object of this invention is the provision of an interrelated and improved method of die casting pumps of this type, especially from aluminum alloys or other light metals.

Another object of the present invention is the provision, in a pump housing of this general type, of improved inipeller receiving and liquid entry recesses and passages to permit such a housing portion to be easily die cast;

, Another and more detailed object is the provision of such a housing having two main intersecting recesses, each being of easily castable form or without any reentrant surfaces therein and one of the die pins used in the die casting of these two passages preferably being embraced by or wrapped around by the other and hence removable subsequently or sequentially only after the removal of said first mentioned die pin.

Another object of the present invention is the provision in an improved pump of this general type having increased efficiency due to the bettering of the impeller entry liquid flow conditions and the reduction of cavitation and turbulence in this entering liquid.

Still another object of the present invention is the provision of a pump of this general type which requires less material, has a smaller impeller entry chamber and hence a smaller diameter in this region, and yet has an equal or greater capacity and efficiency than usual.

A further object of this invention is the provision of an interrelated method of die casting, such pump bodies having a central bore and a generally tangential inlet cavity, permitting the use of single, one-piece, and readily removable die pins in the automatic die casting machine.

A further and more specific object of the instant invention is the provision of a pump of this general type in which there is an increase in pump efficiency due to an energy gain by swirling or pro-rotation of the tangentially entering liquid first by swirl or rotation of the liquid as it moves in through a volute or scrolllike passage around in the direction of pump rotation and with increasing velocity due to the progressively de creasing cross-sectional areas, and secondly due to the swirl or pre-rotation imparted to the liquid by the rotating shaft itself which drags the liquid around with it. Other features, advantages and additional objects of the present invention will be apparent to those skilled in the pump art particularly after consideration of the following detailed descriptions of the several illustrated and presently preferred examples which are correlated to the accompanying sheets of the drawings, wherein like reference numerals refer to like parts and in which:

FIGURE 1 is an elevational view of the outer end of a pump assembly constructed in accordance with the principles ofthe present invention with the drive shaft sectioned and with sections broken awayjand with certain portions dotted in to show the internal structure more clearly; Y

, FIGURE 2 is an enlarged section taken on the lines II--II of FIGURE 1 with liquid flow indicating arrows to illustrate the directions of impeller supply flow;

FIGURE 3 is a reduced scale elevational view similar to FIGURE 1 but showing a second embodiment of a pump assembly according to the present invention;

FIGURE 4 is another reduced scale elevational view similar to FIGURE 1, but showing a third embodiment according to the present invention;

FIGURE 5 is a reduced scale sectional View showing the interior of the intake housing portion of a conventional automotive water pump of this general type, and is included here only for comparison, with the corresponding view of FIGURE 7 showing the present invention;

FIGURE 6 is a sectional view taken on the line VIVI of FIGURE 5 and is likewise included here for comparison with FIGURE 8 which is according to the present invention; I

FIGURE 7 is a sectional viewand shows a somewhat simplified form of the same invention as illustrated in FIGURES 1 and 2 in which, however, the extraand smaller hot water heater water inlet passage is omitted,

and in which the transversely extending die pin used in the die casting thereof is shown solid and as partly withdrawn from its operative position, and the previously fully withdrawn axially extending die pin used in the die casting thereof is here shown in dotted lines (this form may be considered as a fourth embodiment);

ing still another or third form and arrangement of the die casting pins;

FIGURE 11 is a sectional view taken on the line XI-XI of FIGURE 10; and

. FIGURE 12 is 'asectional view like FIGURE 7 show- .ing another or fourth form and arrangement of the of a one-piece metal casting which, is so shaped accord:

ing to the teachings and advantages of the present invention that this or similar housings may be made economically as one-piece die castings, preferably of aluminum alloy or of other light metals. Obviously, other die castable materials may be used when desirable within the purview of this invention.

This housing portion 1 has a preferably fiat face 3 adapted to be suitably secured and sealed in its operative position and with a suitable gasket as by screws or studs through holes such as at 5 in the bosses 6. Here, these screws or studs through holes 5 are, as usual, received and secured into threaded sockets or holes in the engine block itself which forms the other or remaining portion of the pump housing and includes the conventional outlet or discharge passages therefor, as will be well understood by those skilled in this art.

Since the various or conventional arrangements of the pump discharge passages and their enclosing or cavity forming structure for pumps of this type are well known by those skilled in this pump art, and since such discharge passages and the associated pump housing structure are not of themselves part of the present invention, the illustration of such well lmown arrangements or structures is not deemed to be necessary or desirable herein.

The outer or discharge ends of the impeller blades 9 may thus force liquid flow into a suitable chamber which may, if desired, form the usual volute, and thence to one or more distribution passageways to the several regions to which the cooling water is to be supplied.

While not essential in all cases, it is here preferred to have the mixed flow (or serni-centrigual) impeller blade unit 9 formed with a frusto-conical portion on its intake end which is partly recessed into or received in a cavity portion 12 in housing 1. The impeller or blade unit 9 is here preferably made of a thermosetting plastic that adheres to the metal hub insert 16 during the molding process and is thus rigidly connected to form a rigid part of the impeller and shaft unit which is indicated as a whole by 1! It will be understood that various other known interlocking or connecting methods or structures may be used here.

This impeller or blade unit 9 has radially extending blades from whose tips the liquid discharges. The inner portion of the impeller unit 9 comprises the sleeve or hub connecting portion idwhich is suitably and fixedly secured, as by keying, to a reduced end portion 17 of a generally annular cylindrical hub 19. At the generally axial liquid entry into the blades of the impeller 9, the blades are cut away or cut out in a curve as shown at 14 to give a better liquid entry flow condition.

The hub member 19 is, in turn, suitably and rigidly secured onto the inner and smaller diameter end 21 of the shaft 22 which has an annular groove 23 as shown, and several successively larger diameter portions between shaft portion 21 and the enlarged diameter bearing portion 24 thereof. 24 is received as a bearing (and may include, or comprise, any suitable bearing means) in the largerdiarneter cylindrical bore 25 in the casing 1.

As is well known in this art, the annular end chamber 38 to hold the seal has a vent hole or passage 27 to the outside air to vent the back or dry end of the seal to the atmosphere as will be well understood in this art.

T he outer or driven end of this shaft 22 has a suitably reduced diameter portion 26 which extends out through the casing in conventional fashion, and is here shown broken away since its drive connections are well understood by all workers in this art as normally comprising a suitably and rigidly mounted fan hub member thereon to be secured to the fan and to the pulley for the usual belt drive of this shaft 22 and its pump.

Portion 21 of the shaft extends rotatably through a friction type seal for liquid of any conventional or suitable type and which is here designated as a whole by 3! In its present embodiment, this seal 30 may comprise an annular recess forming cup member 32 having an outwardly extending lip 33 and the annular recess opening 34. Lip member 33 abuts or engages against the vertical end wall 35 of the housing cavity 36 which forms the impeller entry chamber or entry bore portion. This cup member 32 is suitably (and usually non-rotatably) mounted in the cylindrical bore 38 in the housing. This bore 38 is of a smaller diameter than the connecting bore 36. A suitable annular sealing ring 40 is circumferentially enclosed in the annular recess 34 of the said cup 32 and has one of its end faces engaged and resiliently biased by spring means such as the compression spring 42 extending into the cutaway recess of ring 40. The other end of spring 42 engages against the bottom of recess 34 of the cup member. The outer periphery of the seal nose piece or seal ring 40 is confined in the generally tapering sleeve member 41 which is in turn engaged by the corner of the cup recess 34. Thus, the inward flat sealing face of the seal ring 40 is resiliently held against the smooth, fiat and seal forming surface 44 on the outer end of hub member 19. This seal member 40 may, as is well known in this art, be of a suitable material such as carbon, ceramics or thermosetting plastics mixed with metal and graphite.

As will be apparent, the inner and outer surfaces of the seal nose piece or annular sealing ring 40 are thus held to secure it in its operative position in the cup member 32.

As shown, the casing member 1 has an enlarged and connecting flange portion 44 having the flat engaging surface 3 on one end thereof. This portion 44 is connected by the generally tapering outer portion 45 to a reduced diameter, outer end portion 46. The generally transversely extending intake passage portion 48 is formed, preferably integrally, with the said casing and preferably having at least in its inner end portions thereof progressively decreasing cross-sectional areas which diminish in the direction of the liquid or water flow.

The diminishing cross-sectional area passage 50 leads into the chamber or annular recess 36 which forms the pump inlet cavity or annular chamber.

This pump housing may include the conventional means for the return of the hot water heaters water into the pump intake which here comprises the nipple or generally cylindrical extension 51 having the passage 52 extending therethrough into the pump inlet cavity 36. As will be understood by those skilled in this art, the heater return hose may be secured on and over the nipple 51.

As shown in dotted lines in FIGURE 1, the impeller 9 preferably has generally backwardly tipped blades.

' Various changes or modifications in the application or forms of the various parts of this pump may be used within the scope of this invention as claimed herein. For examples of such modifications, the pump impeller blades may be of the well known substantially radial type as shown in FIGURE 3 in connection with the rotational direction arrow. Alternatively, the impeller blades may be of the also well known forward tip type as shown in FIGURE 4 in connection with the rotational direction indicating arrow. For ease of comparison, these two additional embodiments illustrated in pumps are the same as that of FIGURES 1 and 2 and hence carry similar reference characters increased by 100 and 200 respectively for convenience in comparison.

Accordingly, it is believed that no further or additional detailed disclosure of these two additional forms of FIGURES 3 and 4 is needed in this disclosure.

For convenience, FIGURES 5 and 6 have reference characters which are similar for analogous parts to those used in FIGURES 1 and 2 except that they are increased by 300.

FIGURES 5 and 6 are included for comparative purposes only and show respectively, an axially extending section through, and a transaxially extending section through, a conventional automotive water pump intake housing casting of this same general type, but which does not include the features of the present invention. This conventional automotive pump housing is for the sake of convenience shown without the hot water heater return nipple such as 51 in FIGURE 1. This type of automotive pump housing is conventional and heretofore has been made of cast iron by the usual or conventional casting processes such as internal sand cores or other procedures permitting casting of the reentrant or of the internally enlarged annular surfaces, as shown at 372 and at 336 in FIGURE 5. Here note the inwardly projecting lip or wall 370. It will be appreciated that these surfaces cannot be cast by use of a one-piece or rigid core or die pin member which can be pulled out or withdrawn axially.

In FIGURE 6 it will be noted that this same impeller inlet cavity or chamber 336 (which in normal use forms an annular chamber about the pump shaft and adjacent to the intake end of its blades) is reentrant or enlarged with respect to the passage 350. Here again, these two surfaces are not castable by a one-piece rigid core member or die pin which can be withdrawn.

It will also be noted that the intake or inlet passage 350 is radial or is directed at the center of the pump shaft and that the water entering therein will divide and go in a rotary fashion around each side of the pump shaft and hence in two directions around the impeller inlet cavity 336. Thus, there is turbulence cavitation and a loss of eificiency due to the flow conditions at the pump entry according to this usual and conventional arrangement and design.

For convenience of comparison, the reference characters in FIGURES 7 and 8 are the same as those in FIG- URES 1 and 2 except that they have been increased by 400. In these two FIGURES 7 and 8 the structure is intended to be identical with that disclosed in FIGURES l and 2 except that the entire pump nipple member 51 of FIGURE 1 has been omitted for the sake of simplicity. It will, however, be understood that such a pump inlet may be employed if desired.

Comparing FIGURE 7 to the corresponding FIGURE 5, it will be apparent that the entire axial bore (comprising the conical surface 412 and the cylindrical surfaces 436, 438 and 425, which are of progressively decreasing diameter towards the outer end of this casing) can readily be manufactured or formed by die casting since a one-piece (and normally steel) die pin 481 can form all of these surfaces to a high degree of accuracy and also can readily be withdrawn to the right as shown in FIGURE 7.

While the other portions of an automatic die casting machine are not shown here except for the die pin 481, it will be readily apparent to those skilled in the art of die casting that this axial bore can readily be die cast.

It is to be noted that the die pin 481 is shown in dotted lines since it is intended that it is to be withdrawn first before the pin 482 is withdrawn. As shown in FIGURE 8 it will be seen that the inner portion of the die pin 482 has a hooked or curved portion 483 which embraces or engages around behind the die pin 481. This hooked or curved portion 483 of the die pin 482 serves to define the outer surfaces for the novel type of impeller inlet cavity according to the teachings of this invention. It will be noted that this cavity is of progressively decreasing cross-sectional area and wraps or extends around the shaft in the form of a partially shaft enclosing annular like chamber to thus impart a swirl or rotation in one direction only to the entering water. Die pin 482 is shown as partly withdrawn to more clearly indicate its structure with respect to the casing.

Here again, it will be apparent to those skilled in the art of die casting that the transversely extending water inlet passage 45% together with its curved end portion 454 of progressively decreasing cross-sectional area and which wraps part way around the pump shaft, can readily be formed in an automatic die casting machine of aluminum, other light metal, or other die castable ma terials, and with these inner surfaces defined by a readily withdrawable one-piece die pin such as 482.

. sectional area.

It will be also noted that the volume and the crosssectional area of the impeller inlet cavity such as 36 or 436 according to the present invention is materially smaller than the volume and also the cross-sectional area of the corresponding pump inlet cavity in a previous or conventional pump of this type as shown at 336 in FIG- URE for purposes of comparison. Thus the pump according to the present invention uses less material in its outer housing portion and is of smaller diameter in this housing portion, thus giving rise to additional savingsin material.

As'noted above, this smaller volume and area and particularly its more efiicient directing of the entering liquid gives rise to a higher pump efiicicncy by reducingor avoiding turbulence and cavitation and by also imparting a progressively increasing velocity in the same direction as the rotation of the pump and its shaft due to the progressively decreasing cross-sectional area of this pump inlet cavity and similarly in the communicating pump intake passageway 45%. It will be noted that the inner portion of this pump intake passageway 51) or 459 has an inner end portion also curved as shown in FIGURES 2 and 7, so that it too is of progressively decreasing cross- If desired, the entire length of this passageway may be substantially tapered although this is not essential to the-practice of this invention.

To cooperate in producing the desired rotation or swirl of the entering Water, passage 50 or 450 is preferably tangential (or substantially tangential) to the annular pump inlet cavity 436 or 36. This is in contrast to the substantially radial inlet passageway 350 of FIGURE 6, which intersects or is directed at the center or axis of the pump shaft. Y I

Referring to FIGURE 7, it'will benoted that the passage 450 is shown as being at approximately 90 to the pump shaft axis. It will, however, be understood that this direction-may be changed within considerable limits without losing the major benefits of the present invention. or 448 (and accordingly its passage 50 or 450) be inclined to the left as seen in FIGURE 7 so that the angle between the driven end of the pump shaft and the axisxof this passage is preferably less than 90 to thus add a higher axial component to the Velocity of the liquid entering the pump inlet cavity and on into the pump itself.

To enjoy all of the benefits of the present invention the entering liquid or fluid should be rotated or swirled in the direction of the pump rotation by two different means. First, as noted above, the entering fluid is rotated by the tangential and the partially wrapping or partially annular inlet passageway 450 and its inner inlet cavity and wrapping portion. Secondly, the entering fluid is preferably rotated by the rotary drag of the shaft itself.

It will be seen from FIGURES 1 and 2 that the liquid in the inlet cavity 36 will be rotated or dragged around in the direction of shaft rotation by the shaft or its hub portions and related structures. This is in contrast to the loss of this frictional drag energy in a conventional form of pump as indicated in FIGURES 5 and 6 in which it will be apparent that only one half approximately of the annular. recess 336 can be in the direction of shaft rotation while the other half will have its flow direction opposed to that of the shaft rotation.

These features materially increase the pump eiiiciency and will permit a smaller and hence a lower cost unit for a given application.

The advantages of die casting for automotive parts or in fact for any mass produced part are so well known as not to need explanation here. Even with the use of the more expensive aluminum alloyinstead of the previously used cast iron the practice of this invention gives rise to substantial savings in the entire cost of the finished part disclosed herein. Indeed, it has been reliably estimated that a pump intake housing portion made according to In fact, itmay be preferred that the extension 48 i the present invention for a competitively priced small American mass produced automobile results in a saving of from 30 to 35 cents apiece in this highly competitive and highly developed art.

Referring again to FIGURE 1 and to its backward tip blades 9, the operating theory relating thereto indicates that the maximum theoretical pressure obtainable at the pump outlet is slightly reduced by the pre-rotation given to the entering liquid by the two means discussed above. This slight pressure loss or velocity gain can readily be compensated for by either increasing the outer diameter of the impeller or by running the pump faster. However, in lieu of these solutions it is usually preferred to increase the ptunps inlet vane angle which is shown by the angle B in FIGURE 1 and is the angle between the tangent to the root of the blade and the root section of the blade. Accordingly, in the case of the present invention this angle B will be preferably increased over the value for the similar angle which would be used in a pump of conventional design and form. An increase in the overall efficiency is gained by this increase in the inlet vane angle.

t is also to be understood that the pump body structure or form, as disclosed above, may be formed in various other ways or by other die casting methods or arrangements of the die pins in the die casting machine.

Forexarnple, as shown in FIGURE 9 (in which the reference characters, except for the die pins, are the same as those used for the same pump structure of FIGURES 7 and 8) the entire axial bore may be formed or defined by two pins instead of one.

Here, the central bore of the same pump casing as in FIGURE. 7 is formed by the two pins including die pin 531a which is, preferably but not necessarily, a fixed pin in the more or less stationary or the fixed cavity forming part ofthe die in the die casting machine. Pin 581b, defining the rest of this central bore, may, preferably, be attached to the movable or sliding ram or cavity closing portion of the die casting machine. As illustrated here, it may be desirable in some cases to have the fixed pin, such as SSla shorter and hence more rigid. Hence it ends at the center end of the seal cavity 438. It is to be noted that this pin arrangement permits the bearing bore, such as 425a, to be larger in diameter than the seal cavity 438, which may be desirable in some applications. It will be understood that in all of these cases the draft of the various cavities will be conformed to the direction in which the pin is to be pulled.

The third or inlet passage forming transverse die pin 582 (which is the same as pin 482 in FIGURES 7 and 8) would preferably be actuated by an auxiliary movable ram, which, is this case the automatic die casting machine would be arranged to move the auxliary ram and pull pin 582 only after pin 481 or pin 5815 had been sufficiently removed. The interrelated method of die casting will be apparent from the foregoing. It may be noted that the form or shape of the inlet passage and extension such as St or 450 may be virtually of any shape so long as its pin can be withdrawn after the cast metal solidifies. Preferably, the outer end will be circular for attachment of the usual hose.

Another example or embodiment of the methods of die casting and of the forms and arrangements of the die pins IS shown in FIGURES l0 and 11, wherein the reference characters, except on the die pins, are the same as those of FIGURES 7 and 8. In this method, the central or axial bore may be die cast by a method using two die pins 681a and $112, as shown. It will be noted that these two pins meet here at the juncture of the seal cavity 438 and the bearing bore 425. The bearing bore 425 may thus be smaller in diameter than the seal cavity, as is usually desired.

In this arrangement, there is still an embracing or surrounding relation between the pins for the inlet passage and the volute or inlet chamber broadly as in FIGURES 9 7 and 8 but here pin 681i; is notched or slotted as shown at 683 to embracingly fit or receive the curved end 685 of pin 682a which thus defines half (or some other fraction) of the circumference of the inlet chamber. Here then, in the method of die casting, pin 682a will be withdrawn or pulled first by its auxiliary ram in the automatic die casting machine to thus permit the timed and subsequent withdrawal of pin 681b preferably with or accompanying the opening of the movable part or closure of the die itself.

As illustrated, in FIGURE 12, which is otherwise just like FIGURE 10, the above described die casting method may be carried out if desired, by the use of only one die pin such as 781 which is removable from the larger or open impeller of the pump body defining die cavity like the single bore pin 481 of FIGURE 7.

The interrelated novel methods of die casting this novel pump body will thus be apparent to those skilled in the die casting art.

It is to be particularly noted that the two passageways or main recesses opening into the pump housing 1 are communicating and generally transverse to each other. Both are die cast into this housing portion. In order to more readily define the non-reentrant or the non-internally enlarged nature of the internal surfaces of these two intersecting passageways or to thus define a die castable surface in which a single rigid die pin may be used, such passages or surfaces may herein be defined as permitting the withdrawal of a one-piece or integral die pin in the die casting machine or process. Thus, this definition means that all such internal surfaces are free of any reentrant internal surfaces which would preclude such rigid pin die casting.

Attention is also directed to the fact that these two openings or recesses are each of either uniform or of progresssively descreasing cross-sectional areas from their outer or die pin withdrawal ends and thus permit the ready withdrawal of a one-piece die pin. This type of internal surface according to the present invention is herein defined for the purposes of this application and its appended claims as one in which all internal or interior cross-sectiontional areas and surfaces are at most equal to succeeding cross-sectional areas inward from the open or pin entry end of such recesses.

It will be understood that terms such as one piece or rigid as used herein are intended to embrace or include the optional casting into the pump casing member of suitable inserts or the like including a seal face insert of ferrous material to form one seal face against a seal cartridge assembled on, and rotating with, the impeller as well known in this art. It is further to be understood that, while the one piece structure, as defined, is preferred yet this invention is not so limited and may be used to advantage in multi-piece assemblies.

It will be understood that the features and advantages of the present invention may be utilized only in part and that various changes or modifications as well as other applications hereof may become apparent to those skilled in this art and used within the scope of the contributions and the novel concepts of the present disclosure, which is to be limited only by the scope of the appended claims.

We claim as our invention:

1. A low-cost one-pice impeller entry housing portion for a generally centrifugal type liquid pump having an impeller, said housing portion having an axially inner end,

a substantially straight axial recess of circular cross section extending axially out from said inner end and including a generally circular cross section impeller entry chamber opening axially and directly into the pump impeller at said inner end for unimpeded flow of the liquid and a substantially straight transverse recess extending laterally and transverse to said axial recess and providing a substantially uniform cross section liquid supply passage opening in from a side of said housing to only one side of said entry chamber along an arc of substantially from substantially tangential to one side of its periphery, said axial recess and said transverse recess each hawng non-reentrant surfaces and internal cross sectional areas which are at most equal to succeeding cross sectional areas inward from their open discharge ends to permit the removal of inter-embracing die pins from said recesses.

2. A generally centrifugal type liquid pump for an automotive type engine, said pump including I an impeller and a low-cost one-piece housing member having an axially inner end,

a generally circular cross section recess having its axis coincident with the axis of rotation of said impeller, extending axially outward from said inner face and including at its axially inner end a generally cylindrical annular impeller entry chamber extending axially with non-diminishing cross sectional areas to an axially inner open end close to said inner end and immediately adjacent the inlet end of said impeller,

and a liquid intake passage extending transversely to said entry chamber and opening into only one side thereof across substantially one-half its diameter out to a side of said liquid intake passage which is substantially tangential to one peripheral side of said entry chamber,

said intake passage having diminishing cross sectional areas in its flow direction and providing an entry path extending spirally in the liquid flow direction part way around the periphery of said entry chamber,

and a rotary cylindrical impeller drivelportion connected to said impeller, extending axially through said entry chamber to make it annular and fully exposed to liquid enteringfrom said intake passage to help to pre-rotate such entering liquid,

said impeller having backwardly tipped blades of a greater than normal inlet blade angle to correct for said pre-rotation and the resulting increased liquid velocity entering the impeller.

3. The pump of claim 2 including a larger diameter recess in said inner end about and opening directly into the axially inner open end of said entry chamber,

said larger diameter recess closely enclosing the inlet end of said impeller.

4. A low-cost one-piece housing portion and removable cover for the entry end of a generally centrifugal type liquid pump having an impeller for an automotive type engine, said cover having an axial outer end, 7

an axial inner end having a substantially flat face with securing means to retain it against a corresponding housing surface,

an axial recess extending transversely to and axially outward from said inner end face at least to said outer end, said axial recess comprising a generally cylindrical impeller entry chamber opening transversely to and spaced axially outwardly from said flat inner end face of said cover, and a reduced diameter end chamber extending outwardly from said impeller entry chamber,

a transverse recess extending laterally in and transversely intersecting said entry chamber to one side of its axial center,

said second recess providing a liquid supply passage located alongside of and closely adjacent said inner end face and opening into said entry chamber in embracing relation thereto and across a radial Width thereof extending in from coolant pump adapted to be secured to an engineblock over a cavity receiving the'impeller and providing a pumping chamber around the impeller which comprises a metal body havin'g a'n end flange with a front face adapted to be sealed against an engine block, a tubular portion'extend- "ing axiallyfrorn said endfiange, a nipple portion depending from said'tubular portion in angular relation therewith, and an axial bore'throughthe body with an inboard end adjacent said end-flange defining an entry chamber for the pumping chamber, an outboard end providing an impeller shaftbearingsupport and an intermediate portion oflarger diameter than the outboardend and of smaller diameter than theinboard end providing a seal chamber, said nipple-defining an inletpassageway to said entry chamber portion of the bore on one side of the axial center thereof and curving at a progressively decreasing depth into merging relation With the bore at the side of 'the bore remotefrom the nipple to provide a swirl recess in the bore enhancing liquid flow to the entry chamber,

and said boreand said passageway having non-increasing cross sectional areas from the flange and outer end of the nipple respectively and being free from reentrant surfaces whereby the body may be die cast with its internal areas and surfaces-permitting the removal of die-pins from the bore and passageway.

6. A low-cost one-piece housing and removable cover adapted for the'entry end of a centrifugal impeller type 'enginecoolant pump and to be secured to an engine block 'overa cavity receiving the impeller and providing a pumping chamber around the impeller which comprises a metal body having an end flange with a front face adapted to be sealed against an engine block, a tubplar portion extending axially from said end flange, a nipple portion depending from said tubular portion in angular relation therewith, and an axial bore through the body with an inboard end adjacent said end flange defining an entry chamber for the pumping chamber, an outboard end providing an impeller shaft bearing support and an intermedia'te portion of smaller diameter than the inboard end providing a sealing chamber, said nipple defining an inlet passageway to said entry chamber portion of the bore on one side of the axial center thereof in eccentric relation therewith and curving at a progressively decreasing depth into substantially tangential merging relation with the entry chamber portionot the bore at the side of said bore remote from the nipple to provide a swirl recess in the bore enhancing liquid flow to the entry chamber, said bore and passageway being free from reentrant surfaces, the relative cross sectional areas of the inboard, outboard and intermediate portions of the bore being dimensioned whereby die pins may be axially retracted from opposite endsof the body, and said passageway having non-increasing cross sectional areas from the outer end of the nipple whereby a die pin may be removed from the nipple and the entire body may be die cast as one piece permitting the removal of all the removable pins without damage to the casting.

References Cited in the file of this patent UNITED STATES PATENTS 820,439 Ray May 15, 1906 973,850 Boucher Oct. 25, 1910 1,128,822 Sparks Feb. 16, 1915 1,308,108 Peterson July 1, 1919 1,404,525 Hotchlriss Jan. 24, 1922 2,204,912 Riebel et a1 June 18, 1940 2,381,834 Meredew et al Aug. 7, 1945 2,542,902 Ch'ubbuck Feb. 20, 1951 2,808,627 Venus Oct. 8, 1957 2,837,792 Ring June 10, 1958 2,976,809 Bushhorn et a1 Mar. 28, 1961 FOREIGN PATENTS 391,413 France Oct. 28, 1908 1,068,014 France Feb. 3, 1954 180,823 Great Britain June 8, 1922 461 ,227 Great Britain Feb. 12, 1937 

1. A LOW-COST ONE-PICE IMPELLER ENTRY HOUSING PORTION FOR A GENERALLY CENTRIFUGAL TYPE LIQUID PUMP HAVING AN IMPELLER, SAID HOUSING PORTION HAVING AN AXIALLY INNER END, A SUBSTANTIALLY STRAIGHT AXIAL RECESS OF CIRCULAR CROSS SECTION EXTENDING AXIALLY OUT FROM SAID INNER END AND INCLUDING A GENERALLY CIRCULAR CROSS SECTION IMPELLER ENTRY CHAMBER OPENING AXIALLY AND DIRECTLY INTO THE PUMP IMPELLER AT SAID INNER END FOR UNIMPEDED FLOW OF THE LIQUID AND A SUBSTANTIALLY STRAIGHT TRANSVERSE RECESS EXTENDING LATERALLY AND TRANSVERSE TO SAID AXIAL RECESS AND PROVIDING A SUBSTANTIALLY UNIFORM CROSS SECTION LIQUID SUPPLY PASSAGE OPENING IN FROM A SIDE OF SAID HOUSING TO ONLY ONE SIDE OF SAID ENTRY CHAMBER ALONG AN ARC OF SUBSTANTIALLY 90* FROM SUBSTANTIALLY TANGENTIAL TO ONE SIDE OF ITS PERIPHERY, SAID AXIAL RECESS AND SAID TRANSVERSE RECESS EACH HAVING NON-REENTRANT SURFACES AND INTERNAL CROSS SECTIONAL AREAS WHICH ARE AT MOST EQUAL TO SUCCEEDING CROSS SECTIONAL AREAS INWARD FROM THEIR OPEN DISCHARGE ENDS TO PERMIT THE REMOVAL OF INTER-EMBRACING DIE PINS FROM SAID RECESSES. 